I fast mine every saturday. mainly because he is a pig and I am overly worried about him getting constipated. I stay at my boyfriend's every weekend, so I feed him Friday normal (throught out the day and definetly before I leave), then saturday nothing, sunday he gets fed in the afternoon/evening.

Yea, tank raised Bettas will eat and eat like no tomorrow. More of a natural instinct as wild Bettas don't know when their next meal is going to come so they will gourge themselves when food is available. I let my boy go hungry once a week as well.